Photonic crystal devices provide potential for controlling light in various configurations. For example, photonic crystal fibers have been formed by configuring a glass fiber with a series of longitudinal holes arranged in a specific pattern that provides confinement to light propagating along the fiber.
Photonic crystal devices have not yet, however, experienced significant penetration into the marketplace. One of the reasons for this is the difficulty in fabricating photonic crystal fibers, which makes these devices expensive.